import math
class A:
    def __init__(self,list1):
        self.list1=list1
        self.result = 0
        self.arg= round((sum(self.list1)/len(self.list1)),3)
        self.list2=[]
        for i in self.list1:
            i=round((i-self.arg),3)
            self.list2.append(round(math.pow(i,2),6))
            
        for each in self.list2:
            self.result += each
        print(math.sqrt(self.result/(len(self.list1)-1)))

list1=[1000.75,1000.82,1000.79,1000.85,1000.84,1000.73,1000.91,1000.76,1000.82,1000.86]
a = A(list1)

